Syringes are used by medical personnel to withdraw blood from patients, inject intravenous medications into patients, inject intramuscular medications into patients, prepare irrigation solutions, prepare dialysis fluids, prepare intravenous pushes, prepare bolus fluids, prepare intravenous fluids for parenteral injection, and prepare oral dose medications. Personnel trained to prepare solutions, pushes, or other fluids for injection prepare the solutions within a laminar flow hood or a vertical flow hood using aseptic technique. The hood provides a work area which reduces the probability of contaminants being introduced into the intravenous admixtures or other solutions during their preparation. Vertical flow hoods and biohazard hoods additionally reduce the probability of escape of biohazard materials being used from the work area and hood. The intravenous fluids, admixtures, and other solutions are prepared by placing a bag or bottle of fluid for injection, along with a needle, syringe, and the injectable medication, into the delineated work area in the hood. The medication is drawn from an ampoule or vial, for example, into the syringe using a needle and is then injected into the bag of intravenous fluid for injection. The fluid for injection can be a push bag, minibag, large volume parenteral, lipids or fat emulsion, etc. The bag or bottle of fluid for injection, apart from its therapeutic value, functions as a vehicle for delivering the medication, electrolytes, or other additives to the patient intravenously.
The individuals preparing the intravenous solutions are typically gowned, gloved, and use aseptic technique during the course of preparing the intravenous fluids. When preparing solutions for injection, it is necessary for the individual preparing the intravenous fluids to move their hands in and out of the laminar flow work area and also out of the laminar flow hood. Accordingly, while the hands are outside the work area and the hood, contaminants in the outside environment are introduced onto the hands or gloves of the individual preparing the intravenous solutions. In addition, the outer packaging used to hold the intravenous additives, ampoules, vials, syringes, needles, and other items used in preparing the solutions is not sterile and can carry contaminants which can be transferred or deposited onto the hands and fingers or gloves of the individual preparing the intravenous admixtures. While aseptic technique is used by the personnel preparing the solutions to reduce the tendency of introducing contaminants into the solutions being prepared, these contaminants can gain entry into the medication that has been drawn-up into the syringe barrel by their being deposited onto the inside surfaces of the syringe barrel by way of the barrel opening and/or plunger. Although not encouraged, inadvertent contact of the plunger shaft typically occurs with the hands, fingers, or gloves during the preparation of a solution. If the air, hands, fingers, or gloves are carrying contaminants such as dirt, lint, viruses, bacteria, microorganisms, dust, germs, pathogens, paper fibers, etc., then these contaminants can be deposited onto the plunger shaft surface and/or fall into the rearward barrel opening and subsequently be deposited onto the inner barrel walls. While a handle portion is usually located on the rearward end portion of the plunger to aid an individual in sliding the plunger into and out of the syringe barrel, larger syringes are typically difficult to handle using only one hand, or even both hands, because of the syringe size, plunger length, and friction created by surface area contact between the internal wall surfaces of the syringe barrel and the plunger piston surface. As a result, the plunger is often grasped by its shaft to gain leverage for aiding the individual preparing the intravenous fluids in pulling the plunger and piston along the hollow or cavity of the inner syringe barrel length to draw medication into the syringe cavity. Because the barrel end is open, grasping the plunger shaft allows contaminants present on the hands, fingers, or gloves to be deposited on the plunger shaft. These contaminants may also fall into the rearward end opening of the syringe barrel and contact the inner surfaces of the syringe barrel. The outside surfaces of the piston and the medication in contact with the inside syringe barrel surfaces can pick up these contaminants and ultimately deliver them to the solutions being prepared. Syringes and plungers currently in use do little to discourage the introduction of contaminants onto the plunger shaft and inner syringe barrel surface. The current syringes also suffer from problems of piston failure or detachment of the piston from the forward end of the plunger shaft causing loss of the seal between the piston and the inner surfaces of the syringe barrel. When this occurs, medication in the syringe barrel leaks or flows out of the syringe barrel rearward end opening and onto the hands, fingers, gloves, and work surface. When the material is blood or the medication or additive being used to prepare the solutions is a biohazard material such as certain chemotherapy drugs, acids, or radioactive pharmaceuticals, the safety of the individual working with the material is compromised because of exposure to and contact with the hazardous material.
On occasion, nurses or other personnel are required to prepare intravenous admixtures because of a patient""s immediate requirement for a medication. These admixtures are prepared in non-sterile environments and generally without the use of aseptic technique. The syringes of the instant invention provide an added level of protection to the medication when working in a non-sterile environment.
An additional problem which plagues current syringe designs is the problem resulting from pulling the forward end of the plunger and piston to close to the rearward end opening of the syringe barrel cavity leading to accidental separation of the plunger from the barrel. Also, when the piston and forward end of the plunger are withdrawn along the syringe barrel cavity and positioned close to the rearward syringe barrel opening, the plunger shaft and medication in the syringe cavity is in increased jeopardy of contamination. Additionally, any rocking motion caused to the plunger shaft while in this position tends to compromise the seal between the piston and the syringe barrel inner surface causing leaking of the medication.
The instant invention overcomes the drawbacks noted above.
This invention relates to a new and improved syringe for use in withdrawing blood from patients, injecting intravenous medications into patients, preparing pre-filled syringes with medications for injection, preparing irrigation solutions, preparing dialysis fluids, preparing intravenous pushes, preparing bolus fluids, preparing intravenous fluids, preparing large volume parenterals for intravenous injection, preparing oral dose medications, and preparing medications requiring chemotherapy drugs, acids, or radioactive pharmaceuticals, etc.
In a first embodiment of this invention, it is an object to provide a new and improved syringe having a corrugated sheath, cover, or shield concentrically enveloping a plunger shaft. The forward end terminus of the corrugated sheath, cover, or shield is attached or molded to the rearward end face surface of the syringe barrel handle member which is formed, or molded, on the rearward end terminus of the syringe barrel. The rearward end terminus of the corrugated sheath, cover, or shield is attached by molding, fusing, adhesives, ultrasonic bonding or welding, thermal bonding, etc., to the forward face surface of a plunger handle member which is also centrally molded, or formed on the rearward end terminus of the plunger shaft. The rearward end terminus of the plunger shaft is centrally molded to the forward face surface of the plunger handle member with the forward end and body of the plunger shaft extending and movably fitted into the cavity, fluid reservoir, or hollow portion of the syringe barrel. The syringe barrel is formed with two open ends at opposite ends of the syringe bore or cavityxe2x80x94one end having a larger diameter opening than the opposite end. The larger diameter opening is located at the rearward end terminus of the syringe barrel. The smaller diameter opening is located at the forward end terminus of the syringe barrel and has a reduced diameter neck at the entrance/exit port. The corrugated sheath, cover, or shield encloses and surrounds the rearward end portion of the plunger shaft extending between the syringe barrel handle member and the plunger handle member. The sheath encloses and surrounds that portion of the longitudinal axis of the plunger shaft located and housed within the central cavity or hollow of the corrugated sheath and between the barrel handle and plunger shaft handle when the corrugated sheath is in a compressed state and in a lengthened state. Thus, the plunger shaft and rearward end syringe barrel opening are closed off from and not exposed to the outside environment. The plunger shaft is withdrawn from the syringe barrel cavity or hollow by grasping the syringe barrel outer surface with one hand and the plunger shaft handle member and/or corrugated sheath outer surface with the other hand and pulling the plunger shaft handle member and/or corrugated sheath such that the plunger shaft emerges from the hollow or cavity of the syringe barrel through the rearward end opening of the syringe barrel. The peaks and walls of the corrugations, pleats, or folds in the sheath are caused to separate along the longitudinal axis of the sheath thereby lengthening the sheath along its longitudinal axis. The plunger shaft remains centrally located within the hollow of the corrugated sheath as the plunger shaft emerges from the cavity and rearward end opening of the syringe barrel. As the corrugations or folds in the sheath separate, the corrugated sheath lengthens enabling the plunger shaft to be withdrawn from the hollow or cavity of the syringe barrel. The corrugated sheath lengthens concentrically around and along the plunger shaft. That is, the corrugated sheath lengthens and encloses a greater length of the plunger shaft as the plunger shaft is further withdrawn from the syringe barrel hollow. The sheath remains in the lengthened or elongated position until a force is applied longitudinally to the plunger shaft to compress or collapse the folds or corrugations of the sheath together. That is, it is not necessary for an individual to hold the withdrawn plunger or lengthened corrugated sheath such that it remains in its lengthened state. The corrugated sheath is designed and manufactured such that it does not automatically recoil. A force must be applied along the longitudinal axis of the syringe plunger shaft and corrugated sheath to cause the ends of the elongated corrugated walls of the sheath to be moved toward each other such that the corrugated sheath shortens. When the walls of the corrugated sheath are forced together, the sheath shortens. Shortening of the corrugated sheath is performed by pressing or applying a force to the plunger member such that the forward end face surface of the plunger handle member advances toward the rearward end opening of the syringe barrel to cause the sheath to shorten and the plunger shaft and piston to slide along the longitudinal axis of the syringe barrel cavity toward the syringe entrance/exit port such that medication in the syringe barrel cavity is ejected from the syringe through the entrance/exit port. The piston rim slidably engages and maintains a tight seal with the internal wall surfaces of the syringe barrel cavity as the piston advances. The liquid medication in the cavity remains forward of the piston head during advancement of the plunger and piston such that the medication in the syringe barrel cavity is ejected from the syringe cavity through the entrance/exit port or forward end opening. An advantage of using the corrugated sheath is the protection provided by the sheath to the plunger shaft and the internal cavity wall surfaces in that contaminants deposited onto the external wall surfaces of the corrugated sheath or syringe barrel will not jeopardize the sterility of the inner cavity of the syringe barrel because the contaminants cannot penetrate the corrugated sheath or syringe barrel. Additionally, the corrugated sheath is designed to elongate only to a length that enables the piston rim to be aligned with the maximum increment reading on the syringe barrel wall which functions to prevent separation of the plunger from the rearward end opening of the syringe barrel
In a second embodiment of the instant invention, it is an object to provide a new and improved syringe having a corrugated barrel. The syringe barrel has a straight segment and a corrugated segment. The corrugations are molded into the syringe barrel to form the corrugated segment at a point on the barrel that is greater than the maximum volume increment reading on the straight segment of the syringe barrel. Thus, the syringe barrel has a straight segment and a corrugated segment. The straight segment is located on the forward end of the syringe barrel and the corrugated segment is located at the rearward end of the syringe barrel. The straight segment and the corrugated segment are continuous with each other. A plunger handle member is molded to rearward end of the syringe barrel at the terminus of the syringe barrel corrugated segment. The rearward end terminus of the plunger shaft is centrally molded to the forward face surface of the plunger handle member. A rearward portion of the plunger shaft body is enclosed or surrounded by the corrugated segment of the syringe barrel. The syringe barrel is formed with an open end and a closed end. The closed end is closed by the plunger handle member which is molded to the rearward end of the syringe barrel at the terminus of the syringe barrel corrugated segment. The open end is located at the forward end terminus of the syringe barrel and has a reduced diameter neck at the entrance/exit port. A forward end portion of the plunger shaft body and a piston located at the forward end terminus of the plunger shaft is movably fitted into and enclosed or surrounded by the straight segment of the syringe barrel. The piston and plunger shaft body are caused to traverse the longitudinal axis of the syringe barrel cavity, fluid reservoir, or hollow by grasping the outer syringe barrel surface with one hand and the plunger shaft handle member and/or external walls of the corrugated segment with the other hand and pulling the plunger shaft handle member and/or corrugated segment such that the forward face surface of the plunger handle member moves away from the straight segment of the syringe barrel causing lengthening of the syringe barrel and elongation of the corrugated segment. Simultaneously, the plunger piston mounted or attached by fusing, molding, adhesives, ultrasonic bonding or welding, thermal bonding, etc., to the forward end terminus of the plunger shaft slidably engages the internal wall surfaces of the straight segment of the syringe barrel as the piston longitudinally traverses the cavity or hollow of the syringe barrel. In order to assist the user in lengthening of the syringe by pulling the plunger shaft handle member, a syringe barrel handle member can be molded to the external circumferential wall surface of the syringe barrel on the straight segment of the syringe barrel at a desired location. The syringe barrel handle member can be used as a wall for leverage to assist the user in lengthening or shortening the syringe barrel while pulling or pushing the plunger shaft handle. The peaks and walls of the corrugations or folds in the corrugated segment of the syringe barrel are caused to separate or spread apart along the longitudinal axis of the syringe barrel as the plunger handle member is pulled thereby lengthening the syringe barrel along its longitudinal axis. At least a portion of the plunger shaft remains centrally located within, and the walls of the piston rim remain in contact with, the internal walls of the hollow or cavity of the syringe barrel straight segment during elongation or lengthening of the syringe barrel. The rearward end terminus of the plunger shaft and the corrugated segment rearward end terminus remain molded to the forward end face surface of the plunger handle member. As the corrugations or folds of the corrugated segment separate or spread apart, the corrugated segment of the syringe barrel lengthens causing the body of the plunger shaft and piston to slide along the straight segment of the syringe barrel cavity in the direction of the corrugated segment and away from the forward end of the syringe barrel. The piston rim is in contact with and forms a seal with the internal cavity walls of the syringe barrel. The corrugated segment encloses or houses and surrounds or encircles a greater length of the plunger shaft body as the plunger shaft and piston are drawn further along the syringe barrel hollow straight segment toward the corrugated segment. Once lengthened, the folds or corrugations of the corrugated segment remain in the lengthened and separated or spread apart position until a force is used to compress or collapse together the folds or corrugations of the corrugated segment. That is, it is not necessary for the individual pulling the plunger handle member and lengthening the corrugated segment to hold the plunger handle member or corrugated segment such that the corrugated segment remains in its lengthened position. The corrugated segment is designed and manufactured such that it does not automatically recoil. This design avoids automatic recoil action and maintains the corrugated segment in the desired lengthened position when drawing medications or other fluids into the syringe barrel. An automatic recoil would force the fluids out of the syringe barrel. An axial force must be applied to the syringe barrel along its longitudinal axis to cause the elongated corrugated segment walls to move toward each other such that the syringe barrel shortens along its longitudinal axis. When the walls of the corrugated segment are forced together, the syringe barrel shortens. Shortening of the corrugated segment can be performed by pressing against the rearward face surface of the plunger shaft handle member in a direction along the axial length of the syringe barrel to cause the corrugated segment to shorten and the plunger piston to slide along the internal side wall surfaces of the syringe barrel cavity toward the forward end and syringe entrance/exit port such that the medication in the syringe barrel cavity is ejected from the syringe through the entrance/exit port. Note that the plunger shaft remains housed within the syringe barrel during operation and non-operation. An advantage of using the straight segment and corrugated segment syringe barrel is the protection provided to the plunger shaft and the internal cavity wall surfaces in that contaminants deposited onto the external wall surfaces of the straight and corrugated segments of the syringe barrel will not jeopardize the sterility of the inner cavity of the syringe barrel because the contaminants cannot penetrate the closed walls of the syringe barrel. Additionally, the corrugated segment is designed to elongate to a length that enables the piston rim to substantially align with the maximum increment reading indicia formed on the syringe barrel straight segment. Because the rearward end terminus of the syringe barrel, at the terminus of the corrugated segment, is molded to the forward face surface of the plunger handle member, and the forward face surface of the plunger handle member is also molded to the rearward end terminus of the plunger shaft, separation of the plunger from the syringe barrel is prevented.
In a third embodiment of the instant invention, it is an object to provide a new and improved syringe having mating concentric plunger member and syringe barrel walls. The plunger member has a cylindrical wall having an open end and a closed end. The closed end of the plunger member has a flat bottom floor structure that forms a hollow cup shape with the plunger member cylindrical walls. It is noted that other shapes other than a flat shape can be provided to the bottom floor structure. The flat bottom floor structure has forward and rearward face surfaces. The flat bottom floor structure can be molded continuous with the plunger member cylindrical walls. The inside diameter of the plunger member is constant along its length. The forward face surface of the flat bottom floor structure has centrally molded thereto the terminus end of a plunger shaft. The plunger shaft is concentrically surrounded by the internal wall surfaces of the plunger member along its longitudinal length. The plunger shaft extends normal from the forward face surface of the flat bottom floor structure along the length of the internal wall surfaces of the plunger member which concentrically surround and enclose or house the plunger shaft. The plunger shaft has a piston mounted, fused, molded, or attached to its forward end terminus. The rim of the piston coincides with the terminus of the plunger member walls at their open end. The syringe barrel is formed with two open ends at opposite ends of the syringe bore or cavityxe2x80x94one end having a larger diameter opening than the opposite end. The larger diameter opening is located at the rearward end terminus of the syringe barrel. The smaller diameter opening is located at the forward end terminus of the syringe barrel and has a reduced diameter neck at the entrance/exit port. The syringe barrel has an outside wall diameter less than the inside wall diameter of the plunger member along its entire length. The inside diameter of the syringe barrel is slightly less than the diameter of the rim portion of the piston. The piston is attached to the forward end terminus of the plunger shaft by mounting, fusing, molding, adhesives, ultrasonic bonding or welding, thermal bonding, etc, such that a tight seal is formed therebetween. The rim portion of the plunger piston mates with and forms a seal with the internal wall surfaces of the bore or cavity of the syringe barrel. The internal and external wall surfaces of the syringe barrel taper at its forward end forming the reduced diameter neck having the smaller diameter opening and an entrance/exit port through which fluid medications and/or other solutions enter and exit the cavity of the syringe barrel. The external wall surface of the reduced diameter neck forms a mating surface for the hub of a needle. At a point rearward of the reduced diameter neck and forward end opening of the syringe barrel, a handle member can be provided on the external syringe barrel wall for assisting the user in sliding of the plunger member relative to the syringe barrel.
The plunger member is mated with the syringe barrel by movably fitting the plunger piston located at the forward end terminus of the plunger shaft into the central cavity, fluid reservoir, or bore of the syringe barrel. As the piston and plunger shaft are slid into the central cavity of the syringe barrel, the internal wall surfaces of the plunger member form a face-to-face relationship with the external wall surfaces of the syringe barrel. The plunger shaft and piston slide into the full length of the central cavity of the syringe barrel such that the head of the piston abuts the tapered internal forward end walls of the syringe barrel. The contour of the head of the piston matches and follows the contours of the tapered internal walls of the syringe barrel to form a seal at the passageway of the entrance/exit port. The terminus surfaces of the larger diameter opening of the syringe barrel can abut with the inner face surface of the flat bottom floor structure of the plunger member. In operation the walls of the outer plunger member walls concentrically surround the syringe barrel walls. In operation, medication is drawn up from a vial or ampoule, for example, by first introducing the needle attached to the external walls of the reduced diameter neck into the vial containing the medication. Next, the internal wall surface of the plunger member is concentrically slid alongside the length of the external wall surface of the syringe barrel while maintaining a concentric glide space between the internal wall surface of the plunger member and the external wall surface of the syringe barrel. Simultaneously, as the plunger member wall is slid along the length of the syringe barrel wall, the piston attached at the forward end terminus of the plunger shaft slidably engages and maintains a tight seal with the internal wall surfaces of the syringe barrel cavity while moving along the syringe barrel cavity and away from the internal tapered walls of the syringe barrel. This causes the air column in the bore or cavity located behind the piston and along the plunger shaft to be expelled or pushed out of the cavity creating a vacuum in the space located between the forward end of the piston head and the internal tapered wall surfaces of the syringe barrel. The vacuum causes the liquid medication in the vial or ampoule to be drawn into the syringe barrel cavity through the needle and the entrance/exit port passageway. The needle is then removed from the medication vial or ampoule and positioned in the needle port of an appropriate bag or bottle of intravenous solution, for example. The liquid medication can then be injected into the bag or bottle of intravenous solution by applying pressure to the rearward face surface of the flat bottom floor structure. This pressure causes the longitudinal length of the plunger shaft and the plunger piston to advance along the cavity of the syringe toward the tapered internal wall surfaces of the syringe cavity. The piston rim slidably engages and maintains a tight seal with the internal wall surfaces of the syringe cavity as the piston advances. The liquid medication remains forward of the piston head during advancement of the plunger and piston. The liquid medication is ejected out of the entrance/exit port of the syringe barrel as the plunger is advanced. An advantage of using the syringe having mating concentric plunger and syringe barrel walls is the protection provided to the plunger shaft and the internal cavity wall surfaces of the syringe barrel in that contaminants deposited onto the external wall surfaces of the plunger member or syringe barrel will not jeopardize the sterility of the inner cavity of the syringe barrel because the design discourages entry of contaminants into the syringe barrel cavity.
An added feature for the third embodiment is to provide a first sealing ring to the inner wall surface of the plunger member at or near its open end terminus. A second sealing ring is formed on the external wall surface of the syringe barrel at or near its large diameter terminus. The sealing rings traverse the entire circumference or perimeter of the surface to which they are formed. The sealing rings are preferably formed of a flexible material and extend from their surface origin a distance less than or equal to the distance to the opposing surface. The sealing rings can have any desired cross-sectional shape such as triangular, square, circular, etc. The sealing rings provide several benefits and advantages. First, the sealing rings seal the glide space existing between the internal wall surface of the plunger member and the external wall surface of the syringe barrel. This discourages entry of contaminants such as dirt, dust, microorganisms, and pathogens, and any other type of contaminant carried by the air, hands, fingers, gloves, etc., that may become deposited onto the external surfaces of the syringe barrel from entering the syringe and becoming deposited on the internal walls of the syringe cavity or in the medication in the syringe barrel. Second, the sealing rings function to prevent accidental separation of the plunger member from the syringe barrel through abutment of the sealing rings as the walls of the plunger are moved relative to the walls of the syringe barrel Third, the sealing rings function as a dam or barrier to medications or other fluids that leak from the syringe cavity and collect or accumulate in the cup of the plunger member due to piston failure.
In a fourth embodiment of the instant invention, it is an object to provide a new and improved syringe having concentric syringe barrels and a plunger member. The plunger member has a wall having an open end and a closed end. The closed end of the plunger member has a flat bottom floor structure that forms a hollow cup shape with the plunger member cylindrical walls. It is noted that other shapes other than a flat shape can be provided to the bottom floor structure. The flat bottom floor structure has forward end and rearward end face surfaces. The flat bottom floor structure can be molded continuous with the walls of the plunger member. The inside diameter of the plunger member walls is constant along their length. The forward end face surface of the flat bottom floor structure has centrally molded thereto the terminus end of a plunger shaft. The plunger shaft can also be molded continuous with the flat bottom floor structure. The plunger shaft is centrally located within and surrounded by the internal wall surfaces of the plunger member. The plunger shaft extends centrally and normal from the forward face surface of the flat bottom floor structure along the length of the plunger member walls. The walls of the plunger member extend normal from the plane of the forward end face surface of the flat bottom floor structure and concentrically surround the plunger shaft. The plunger shaft has a piston attached by mounting, fusing, molding, adhesives, ultrasonic bonding or welding, thermal bonding, etc to its forward end terminus. The rim of the plunger piston coincides with the terminus of the walls of the plunger member at its open end. The concentric syringe barrel is formed with inner and outer syringe barrels. An inner concentric syringe barrel is formed with two open ends located at opposite ends of the inner concentric syringe barrel cavityxe2x80x94one end having a larger diameter opening than the opposite end. The larger diameter opening is located at the rearward end terminus of the inner concentric syringe barrel. The smaller diameter opening is located at the forward end terminus of the concentric syringe barrel and has a reduced diameter neck at the entrance/exit port. The inner syringe barrel has an outside diameter less than the inside diameter of the plunger member walls along the entire length of the inner syringe barrel. The inside diameter of the inner syringe barrel is slightly less than the diameter of the rim portion of the plunger piston which is attached by mounting, fusing, molding, adhesives, ultrasonic bonding or welding, thermal bonding, etc., to the forward end terminus of the plunger shaft. The rim portion of the plunger piston mates with and forms a seal with the internal wall surfaces of the bore or cavity of the inner syringe barrel. The internal and external wall surfaces of the inner syringe barrel taper at their forward ends forming the reduced diameter neck having the smaller diameter opening and an entrance/exit port through which fluid medications and other solutions or fluids enter and exit the cavity of the inner syringe barrel. The external wall surface of the reduced diameter neck forms a mating surface for the hub of a needle. An outer syringe barrel concentrically encircles the inner syringe barrel forming concentric syringe barrels. The internal wall surfaces of the outer syringe barrel are in face-to-face relationship with the external wall surfaces of the inner syringe barrel and are separated by a distance which forms a second cavity or space between the inner syringe barrel wall and the outer syringe barrel wall. This second cavity or space is open at its rearward end and closed at its forward end forming a cup shape. The open end receives the walls of the plunger member. This second cavity or space functions as a glide space for the walls of the plunger member. At a point located at the terminus of the opening on the external wall surface of the outer syringe barrel, a handle member can be provided for assisting the user in sliding the plunger member relative to the inner and outer syringe barrels.
The plunger member is mated with the concentric syringe barrel member by movably fitting the plunger piston, located at the forward end terminus of the plunger shaft, into the central cavity, fluid reservoir, or bore formed by the inner syringe barrel walls. As the piston and plunger shaft are slid into the central cavity of the inner syringe barrel, the internal wall surfaces of the plunger member form a face-to-face relationship with the external wall surfaces of the inner syringe barrel. Also, the external wall surfaces of the plunger member form a face-to-face relationship with the internal wall surfaces of the outer syringe barrel. The plunger shaft and piston slide into the full length of the central cavity of the inner syringe barrel such that the head of the piston abuts the tapered internal walls of the inner syringe barrel. The contour of the head of the piston matches and follows the contours of the tapered internal walls of the inner syringe barrel to form a seal at the passageway of the entrance/exit port. The terminus surfaces of the larger diameter opening of the inner syringe barrel can abut with the inner face surface of the flat bottom floor structure of the plunger member. In operation, the walls of the concentric syringe barrels concentrically surround the plunger member walls. Medication is drawn up from a vial or ampoule, for example, by first introducing the needle, attached to the external walls of the reduced diameter neck of the entrance/exit port, into the vial or ampoule containing the medication. Next, the longitudinal wall surfaces of the plunger member are concentrically slid within the glide space existing between and along the length of the external wall surface of the inner syringe barrel and the internal wall surface of the outer syringe barrel. Simultaneously, as the plunger member wall is slid within the glide space along the length of the external wall surface of the inner syringe barrel and the inner wall surface of the outer syringe barrel, the piston attached at the forward end terminus of the plunger shaft slidably engages and maintains a tight seal with the internal wall surfaces of the inner syringe barrel cavity while moving along the inner syringe barrel cavity and away from the internal tapered walls of the inner syringe barrel. This causes the air column in the bore or cavity located behind the piston and along the plunger shaft to be pushed out of the cavity creating a vacuum in the space located between the forward end of the piston head and the tapered internal wall surfaces of the inner syringe barrel. The vacuum causes the liquid medication in the vial or ampoule to be drawn into the inner syringe barrel cavity through the needle and the entrance/exit port passageway. The needle is then removed from the medication vial or ampoule and positioned in the needle port of an appropriate bag or bottle of intravenous solution. The liquid medication can then be injected into the bag or bottle of intravenous solution by applying pressure to the rearward face surface of the fiat bottom floor structure. This pressure causes the longitudinal length of the plunger shaft and the plunger piston to advance along the cavity of the inner barrel of the syringe toward the tapered internal wall surfaces of the inner barrel syringe cavity. The piston rim slidably engages and maintains a tight seal with the internal wall surfaces of the inner syringe barrel cavity as the piston advances. The liquid medication remains forward of the piston head during advancement of the plunger and piston. The liquid medication is ejected out of the entrance/exit port of the syringe cavity of the inner barrel as the plunger is advanced. An advantage of using a syringe having concentric inner and outer syringe barrels which mate concentrically with a plunger member is the protection provided to the plunger shaft and the internal cavity wall surfaces of the syringe in that contaminants deposited onto the external wall surfaces of the plunger member or syringe barrel will not jeopardize the sterility of the cavity of the inner syringe barrel because the design discourages entry of contaminants into the inner syringe barrel cavity.
An added feature for the fourth embodiment is to provide a first sealing ring to the internal wall surface of the outer syringe barrel at or near its open-end terminus. A second sealing ring can be formed on the external wall surface of the plunger member at or near the terminus of its open end. A third sealing ring can be formed on the internal wall surface of the plunger member at or near the terminus of its open end. Fourth and fifth sealing rings can be formed on the internal and external surfaces of the inner syringe barrel at or near the terminus of its open end. One or more of the above sealing rings can be formed or provided on the wall surfaces of the concentric syringe or plunger member. The sealing rings traverse the entire circumference or perimeter of the surface to which they are formed. The sealing rings provide several advantages. The sealing rings are preferably formed of a flexible material and extend from their surface origin a distance less than or equal to the distance to the opposing surface. The sealing rings can have any desired cross-sectional shape such as triangular, square, circular, etc. The sealing rings provide several benefits. First the sealing rings function as a barrier by sealing the glide space existing between the internal wall surface of the outer syringe barrel and the external wall surface of the inner syringe barrel. This discourages entry of contaminants such as dirt, microorganisms, dust, pathogens, and other types of contaminants, carried by air, hands, fingers, gloves, etc., which may become deposited onto the internal surfaces of the inner syringe barrel cavity. Second, the sealing rings function to prevent separation of the plunger member from the concentric syringe barrels through abutment of the sealing rings on the syringe barrels with the sealing rings of the plunger member as the walls of the plunger member are moved relative to the walls of the inner and outer concentric syringe barrels. Third, the sealing rings function as a dam or barrier to fluids that leak from the syringe barrel cavity and collect or accumulate in the cup of the plunger member due to piston failure.
In a fifth embodiment of the instant invention, it is an object to provide a new and improved syringe having a contaminant shield positioned at the rearward end opening of the syringe barrel. The contaminant shield is formed on the rearward end syringe barrel inner wall surface using a semi-rigid and flexible material. The contaminant shield projects perpendicularly from the circumference or perimeter of the syringe barrel inner wall surfaces into the syringe barrel cavity and surrounds and abuts the surfaces and walls of the ribs which form the spine of the plunger shaft. The contaminant shield can be formed from a single material or a mixture of materials which will provide a semi-rigid and flexible characteristic to the shield. To facilitate attachment of the contaminant shield to the inner wall surface of the syringe barrel cavity, a dovetail groove, or similar locking groove, can be formed in the surface of the syringe barrel inner wall along the circumference or perimeter at or near the rearward end opening of the syringe barrel During the molding process, the dovetail groove receives and anchors the material used to form the contaminant shield. The contaminant shield has a forward end face surface facing the cavity of the syringe barrel and a rearward end face surface facing the plunger handle member.
Alternatively, the shield can be formed of two parts. The first part is formed of a material providing a rigid or hard characteristic or quality to the contaminant shield The first part can be formed of the same material and molded continuous with the circumference of the inner wall surface of the syringe barrel at or near the rearward end opening of the syringe barrel. The first part, when formed, projects into the syringe barrel cavity perpendicularly from the circumference or perimeter of the inner wall surface of the syringe barrel. The first part has a forward face surface and a rearward face surface. The first part has centrally formed therethrough an opening having the shape of the cross-section of the plunger shaft used in conjunction with the syringe barrel. If the contaminant shield is formed separately, or with a different material than that used to form the syringe barrel cavity, then a dovetail groove, or similar locking groove, can be formed on the inner wall surface of the syringe barrel along the circumference or perimeter of the syringe barrel inner wall surface at or near the rearward end opening of the syringe barrel. During the molding process, the dovetail groove receives and anchors the material used to form the first part of the contaminant cover shield.
The second part of the contaminant shield is formed from a soft, flexible material that has a bendable characteristic. The second part is formed within the cross-sectional opening on the periphery of the first part. The second part projects from the periphery or edges of the first part and into the cross-sectional opening. The second part terminates as a flexible lip, edge, or periphery that defines the plunger shaft cross-sectional opening During operation or use, the lip, edge, or periphery of the second part is in contact with the surfaces of the plunger shaft which fits within the cross-sectional opening and traverses the opening as the plunger shaft exits and enters the syringe barrel cavity. The second part is formed on the cross-sectional periphery of the first part. This can be accomplished by providing the external surface of the first part, at its edge or periphery, with a dovetailed shape, or other surface shapes such as slits or holes, which would provide a locking function to the cross-sectional periphery of the first part during its forming operation to which the second part can be formed about. Alternatively, a dovetailed groove or similar locking groove can be provided at and within the cross-sectional periphery or edge of the first part to receive and anchor the material used to form the second part of the contaminant shield. The rearward end terminus of the plunger shaft is centrally molded to the forward face surface of a plunger handle member with the body of the plunger shaft extending through the cross-sectional opening formed in the contaminant shield. The forward end terminus of the plunger shaft has a piston that is attached or formed thereto by mounting, fusing, molding, adhesives, ultrasonic bonding or welding, thermal bonding, etc, and, along with the plunger shaft, is movably fitted into the cavity, fluid reservoir, or hollow portion of the syringe barrel. The syringe barrel is formed with two open ends located at opposite ends of the syringe cavity. The rearward end of the syringe barrel has a plunger shaft cross-sectional opening as described above and the forward end terminus has a small diameter opening. The small diameter opening has a reduced diameter neck at the entrance/exit port. In operation, the plunger shaft is withdrawn from the syringe barrel cavity by grasping the outer syringe barrel surface with one hand and the plunger shaft handle member with the other hand and pulling the plunger shaft handle member such that the plunger shaft emerges from the hollow or cavity of the syringe barrel through the rearward end plunger shaft cross-sectional opening formed in the contaminant shield exposing the plunger shaft to the external environment. During withdrawal, the piston at the forward end terminus of the plunger shaft slidably engages and maintains a tight seal with the internal wall surfaces of the syringe barrel cavity while moving along the syringe barrel cavity and away from the internal tapered walls of the syringe barrel located at the forward end of the syringe barrel. This causes the air column in the bore or cavity behind the piston head and along the plunger shaft to be expelled or pushed out of the syringe cavity through the plunger shaft cross-sectional opening creating a vacuum in the space located between the forward end of the piston head and the internal tapered wall surfaces of the syringe barrel. The plunger shaft remains in a withdrawn position until a force is applied along the longitudinal axis of the plunger shaft in a direction toward the forward end terminus of the plunger shaft to cause the plunger shaft to pass through the plunger shaft cross-sectional opening formed in the contaminant shield and cause the plunger shaft and piston to advance along the longitudinal axis of the syringe barrel cavity toward the tapered internal wall surfaces and entrance/exit port of the syringe barrel. The inside diameter of the syringe barrel is slightly less than the diameter of the rim portion of the piston such that the piston rim slidably engages and maintains a tight seal with the internal wall surfaces of the syringe barrel cavity as the piston advances to maintain liquid medication or other fluid in the cavity forward of the piston head during advancement of the plunger and piston such that the medication or other liquid in the syringe barrel cavity is ejected from the syringe cavity through the entrance/exit port or forward end opening. As the plunger shaft and piston advance along the internal wall surfaces of the syringe barrel cavity, the semi-rigid flexible material or the flexible second part, depending on which contaminant shield design is used, contacts the surfaces of the plunger shaft while it is advanced through the plunger shaft cross-section of the contaminant shield providing a wiping and sweeping action to the surfaces of the plunger shaft in a direction away from the forward end terminus of the plunger shaft as the plunger shaft and piston are caused to traverse the syringe cavity toward the forward end terminus of the syringe barrel thereby aiding in preventing entry of contaminants into the syringe barrel cavity. The sweeping and wiping action functions to push contaminants such as dirt, dust, microorganisms, and pathogens, and any other type of contaminant carried by the air, hands, fingers, gloves, etc, that is subsequently deposited onto the exposed portion of the plunger shaft, in a direction away from the forward end of the plunger shaft and ultimately from entering the syringe barrel cavity by way of the plunger shaft. The contaminant shield also functions to prevent deposition of dirt, lint, viral components, bacteria, germs, dust, microorganisms, pathogens, paper fibers, and any other type of contaminant carried by the air, hands, fingers, gloves, etc., from falling into the rearward end opening of the syringe barrel and becoming deposited onto the internal surfaces of the syringe barrel cavity. The contaminant shield of the instant invention provides protection to the plunger shaft and the internal cavity wall surfaces of the syringe barrel in that contaminants deposited onto the outer surfaces of the contaminant covers will not jeopardize the sterility of the inner cavity of the syringe barrel holding the medication or other fluid because the contaminants cannot penetrate the walls of the contaminant guard or shield.
As an alternative to forming or molding the contaminant shield onto the inner wall surface of the syringe barrel, the contaminant shield can be formed separately from the syringe barrel and attached in a separate operation. For example, the contaminant shield could be formed with a wall extending perpendicularly from the forward face surface of the shield with the outer surface of the perpendicularly extending wall having grooves and/or threads formed thereon which mate with grooves and/or threads formed on the inner wall surfaces at the rearward end opening of the syringe barrel by screwing, turning, twisting, or rotating the threaded end cap contaminant shield into the grooved rearward end opening of the syringe barrel. Additionally, the shield portion of the end cap contaminant shield is formed with either the semi-rigid, flexible material or as the two-part material structure.
A further alternative includes providing a contaminant shield having walls extending perpendicularly from the forward face surface of the shield such that the outer surface of the perpendicularly extending walls have a flange or lip that mates with the inner wall surfaces of the syringe barrel at the rearward end opening through frictional fitting, snap fitting, locking, or a combination thereof.
Still further, the end cap contaminant shield can be manufactured as a flat or plate design without extending walls and having only the forward and rearward end face surfaces comprising first and second parts and an opening in the shape of the plunger shaft cross section. The forward face surface of the end cap contaminant shield is attached, bonded as by adhesives, ultrasonic bonding or welding, thermal bonding, etc., to the rearward end terminus of the syringe barrel. The plunger shaft functions and operates with the flat or plate end cap contaminant shield in the manner as previously described with the other end cap contaminant shield designs.
An advantage of using the shield is the protection provided by the shield to the internal cavity wall surfaces of the syringe in that contaminants deposited onto the rearward end wall surfaces of the shield will not jeopardize the sterility of the inner cavity of the syringe barrel because the contaminants are blocked by and cannot penetrate the shield.
An added function and benefit of the fifth embodiment is that the shield functions to prevent accidental separation of the plunger member from the syringe barrel by abutment of the forward face surface of the shield with forward end terminus of the plunger shaft or piston. Second, the shield functions as a temporary dam or barrier to fluids that may escape the syringe cavity due to piston failure. When the end cap contaminant shield is used, the forward end terminus of the end cap walls function to prevent accidental separation of the plunger member and syringe barrel by abutment of the forward end terminus of the end cap walls with the forward end terminus of the plunger shaft or piston.
The syringes and the components forming the syringes of the instant embodiments can be formed by injection molding, blow molding, extrusion, compression molding, or any other molding process or combination of molding processes that will accomplish the molding objective of forming the syringe components, such that the molded syringe components mechanically operate together to perform the desired function and achieve the desired results. The components used to form the syringes of the instant invention as set forth above in the foregoing embodiments can be formed of plastic materials, polymers, rubber materials, metals, alloys, glass materials, or combinations thereof. The materials used to mold the syringe components will depend on the capacity in which the syringe will be used and the type of solution or fluid with which the syringe will be used. That is, some materials are more stable and safer to work with or store when in glass syringes; while syringes formed with other materials is sufficient for working with other solutions or fluids. The syringe barrels should be substantially transparent so the solutions or fluids in the barrel cavity can be monitored with regard to the volume measuring indicia formed and depicted on the syringe barrel.
The syringes of the instant invention can be used for prepacking medications which will be used orally, for injection, for irrigations, for preparation of other solutions, etc. The syringes of the instant invention can also be used for manufacturing injectable or oral medications as pre-filled or pre-dosed syringes. The materials used to form the syringe components of the instant invention should be compatible with the ingredients of the pre-filled or pre-dosed medication, solution, other substances, etc., contained in the syringe during its storage so as to provide stability and a suitable shelf-life to the medication, solution, other substance, etc. Also, while shelved, the medications, solutions, other substances, etc., pre-filled and pre-dosed in the syringes of the instant invention should be protected in the syringes from adverse effects of moisture, atmospheric oxygen, and/or light when required.
In the case of single-dose, pre-dosed, or pre-filled syringes carrying an injectable or oral medication, a syringe of the instant invention can be manufactured, assembled, and filled with medication or other desired substance. The pre-filled syringe can be manufactured and assembled without a needle. A removable closure cap can be provided for the entrance/exit port at the reduced diameter neck. The user can remove the closure cap and attach a needle to the syringe when the medication is ready to use. Alternatively, the syringe of the instant invention can be manufactured and assembled with the needle as a unit wherein the needle or cannula can be permanently attached by molding, fusing, adhesives, ultrasonic bonding or welding, thermal bonding, etc., to the reduced neck at the forward end of the syringe barrel. A removable needle cap or sheath is provided and can be attached by a tamper-resistant means such that the needle cap or sheath houses or covers the needle and ensures the integrity of the contents of the syringe prior to use and during storage. Alternatively, the needle or cannula with needle cap or sheath can be removably attached to the reduced neck at the forward end of the syringe barrel by screwing, frictional fit, etc. Also, a tamper-resistant means can be provided with the removably attached needle or cannula and needle cap or sheath. The medication pre-filled or pre-dosed in the syringe of the instant invention by the manufacturer, with or without a needle, is packaged for use. The medication pre-filled or pre-dosed in the syringe of the instant invention by the manufacturer can be delivered to an individual as a single dose or as multiple doses. Because of the design of the syringes of the instant invention, the likelihood of contamination to the medications, solutions, fluids, etc., of the pre-filled or pre-dosed syringes is reduced compared to existing syringe designs. That is, an added protective barrier is present protecting the pre-dosed or pre-filled medication in the syringe while shelved. In order to maintain the plunger shaft in a withdrawn position and protect the pre-filled or pre-dosed medication, solution, or other substance, etc., from being inadvertently expelled or ejected from the syringe cavity due to impact or forces to the plunger shaft or other components of the syringe, a brace means can be incorporated which functions to restrict the plunger shaft from traversing the syringe cavity. As an example, a brace means such as a shrink film or tape, tube, cage, etc., can be applied over the corrugated sheath, plunger member, syringe barrel, or combination thereof, in a manner to restrict longitudinal movement of the plunger shaft or plunger member until the brace means is removed.
The syringes of the instant invention can be used for pre-packing or prepackaging medications which will be delivered or taken orally by the individuals. The syringes of the instant invention can be used as containers for holding medications such as antibiotics, etc., which will later be given orally to a patient. The pre-packing or prepackaging of the oral unit dose syringes can be performed or accomplished by a manufacturer which can provide pre-dosed or pre-filled unit dose oral medication syringes containing a desired medication, or the syringes can be used by pharmacy or other personnel or individuals to pre-dose and package oral medications. Because of the design of the syringes of the instant invention, the likelihood of contamination to the medications of the pre-filled or pre-dosed syringes is reduced when compared with existing syringe designs. That is, an added protective barrier is present protecting the pre-filled or prepackaged medication in the syringe while shelved.
The syringes of the instant invention may also be provided with syringe caps which fit or screw onto the reduced diameter neck portion of the forward end opening and function as closures. The syringe caps also function to preserve sterility of the outer surface of the reduced diameter neck and the inner cavity of the syringe barrel.
The syringes of the instant invention can be used advantageously by personnel working in labs, working with radioactive pharmaceuticals, performing tests in hospital labs, doing research in pharmaceutical companies, universities, and any other type of research facility performing research in any capacity such as biological, pharmaceutical, genetic, etc., that require the use of syringes.
Trained personnel, such as those working in hospitals, compounding establishments, etc., can also use the syringes of the instant invention to pre-fill or pre-dose the syringes of the instant invention with injectable or oral medications for delivery to a patient, nursing unit, doctor""s office, other ordering establishment, etc. These personnel can also use the syringes of the instant invention to prepare intravenous admixtures, withdraw blood from patients, inject intravenous medications into patients, inject intramuscular medications into patients, prepare irrigation solutions, prepare dialysis fluids, prepare intravenous pushes, prepare bolus fluids, prepare intravenous fluids for parenteral injection, prepare immunizations for any route of administration, prepare oral dose medications, etc.